Improved safety-valve for steam-generators



e, Unimet) STATES KParitair GFFICE.

VIRGIL D. GREEN, OF WATERTOWN, WISCONSIN.

IMPROVED SAFETY-VALVE `FOR STEAM-GENERATQRS.

Speeication forming part of Letters Patent No. 54,716, dated May 15,1866.

To all whom it may concern.-

Be it known that I, VIRGIL D. GREEN, of

lWatertown, in the county of Jefferson and State of Wisconsin, haveinvented a new and Improved Arrangement of Safety-Valves forSteam-]3oilers; and I do hereby declare that the following is a full,clear, and exact description thereof, which will enable others skilledin the art to make and use the same, reference being hadto theaccompanyingdrawings, forming a part of this specication. n

The object of the present invention is to enable a large safety-valve tobe used for the escape of steam from a boiler, while at the same timethe use of a long lever or heavy weights or rigid and stiff springs aredispensed with; and it consists in arranging upon the boiler, in asuitable aperture thereof, a hollow cupfsliaped valve opening outwardand having an inside diameter greater than the diameter of the saidaperture, which valve, by its open end, plays steam-tight upon a xedcenter-plug or piston, having through its center a passage formedleading to and opening into the boiler, for the steam to pass from theboiler intothe said valve, in the end of which steam-passage, communicating with the boiler, is arranged a val ve opening inward, and soconnected through a suitable stem with another valve of said steampassage, but opening outward, that when one is open the other isclosed,the latter valve being held down by means of a weight, spring, orany other suitable device properly adjusted to the degree of pressurewhich it is desired the steam in the boiler should not exceed. By thisarrangement it is obvious that so long as the pressure of steam withinthe boiler does not exceed the downward pressure upon the weighted valvethe passage of steam from the boiler to the interior ofthe cup-shapedvalve is free and uninterrupted, consequently producing sufficientpressure upon the inside of such valve, as its surface there exposed tothe pressure of the steam is greater than its end fitting in theaperture ofthe boiler and subject to the direct action of the steamtherein to firmly hold it to its seat in the boiler, the valve at theboiler end of the steam-passage leading to the hollow-valve being thenopen, and consequently the weighted valve closed. In this relativeposition the several valves remain until the pressure of the steam inthe boiler has sufficiently increased above that of the weighted valveto raise or open it, consequently at the same time closing the valve in`the steam-passage from the boiler to the cup- Lshaped valve, and thusstopping the passage iof steam through it, through which weighted `valvethe steam in such passage, as well as in the cup-shaped valve, thenescapes to the open air, thereby relieving the inside pressure upon suchvalve, by which it is held to its seat, when the steam-pressure withinthe boiler, immediately raising such valve from its seat, opensit `tothe escape of the steam from the boiler, `which continues so long as theboiler-pressure fis above the pressure of the weighted valve,orfsuftieiently so to hold it open,butis immediately ,stopped the instantthe pressure is reduced bejlow such amount by the falling or closing ofthe weighted valve, and consequent opening ot' 1the boiler-valve in thesteam-passage tothe rcupfshaped valve, whereby the steam-pressure ,againacts upon the inside of the cupshaped valve, bringing or forcing it toits seat, where `it remains until the boiler-pressure again exceeds theamount of pressure on the weigh ted valve, Awhen the same relativemovements ot' the several valves again take place as above explained,and so ou at each and every increase of boilerpressure- In accompanyingplate of drawings myimprovements are illustrated, Figure 1 being a planor top view, Fig. 2 a side elevation, and Fig. 3 a central verticalsection taken in the plane of the line a' a', Fig. l. K

Similar letters of reference indicate like parts.

A in the drawings represents, for instance, the top plate of asteam-boiler, which may be made of any of the ordinary constructions ofsuch boilers, in which boiler-plate an aperture or opening, 15 is formedwith its edge ared or beveled outward. In the dared portion Vof thisopening B tits the beveled or flared lower end, C, of a hollowcup-shaped valve, D, playing steam-tight by its open and upper end, E,over a fixed piston or plunger, F, secured to the under side of the topplate, G, of the chamber or box H surrounding the said valve D. Throughthe. center of this fixed piston or plunger F extends a passage, I,leading therefrom to the top of the boiler, with the interior of whichit communicates through a flared aperture or opening, J, having avalve,K, arranged in it opening inward. This valve K is secured to the lowerend of a vertical rod or stem, L, extending upward through the censteamin the boiler, the weighting of this Valve N being the same as inordinary safety- 4 valves.

From the above description of the arrangement ofthe two valves K and N,attached to a common stem,L, itis obvious that when one is open theother will be closed, and vice versa, the steam, when the valve K isopen, passing through the steam-passage I leading from the boilerdirectlyinto the hollow cup-sh aped valve D, the internal diameter oi'which is intended to be sufficiently in. excess ot' the boiler-aperture,in which it lits or comes to a seat, that the inside pressure of steamwill more than balance the direct pressure of the steam within theboiler upon its lower end, and thus firmly hold it down and to its seat,where it remains until the steam-pressure in the boiler exceeds theamount to which the valve N is weighted, which it consequently thenYraises and opens, at the same time closing the valve K, stopping thepassage of steam through steam-passage l, from which, as well as theinterior of the cup-valve D, the steam then escapes through said openvalve N, relieving' the inside pressure upon the valve D, which then, bythe action of the boiler-pressure upon the lower end, immediately risesand opens, giving a rent to-the steam from the boiler through itsaperture B intothe chamber H, from which it escapes to the open air atR, said valve D, as soon as the boiler-pressure has thus become reducedto the desired amount, falling and closing, while at the same time theweighted valve N closes, (the valve K ofcourse opening,)

and the steam communication is again established with the interior ofthe cup-valve D, which so remains until theboiler-pressure again exceedsthe amountto which the weightedvalve N is adjusted or set. By thisarrangement of the valves K, N, and D so as to operate with regard toeach other, as explained, it is manifest that a small weighted valve maybe used, while at the same time a large vent is obtained for the steamto escape from the boiler in case it should exceed the amount ofpressure desired, the importance of which arrangement is apparent to allconversant with steam-boilers.

In order to assist the closing ofthe cup-Valve D, I use upon its insidea light coiled or spiral spring, S, resting at one end upon the valve Dand at its other hearing against the lower end of the xed plunger F,around which the' valve iits steam-tight.

T is a steam-passage around Valvechamber H and upon the opposite side tosteam-passage I, for the equalizing ot' the expansion oi the saidchamber-plate.

a is a small opening through bottom of cupshaped valve to allowcondensed steam in it to escape.

I claim as new and desire to secure by Letters Patent- The combinationof the cup-shaped or hollow valve D, steam-passage I, and weighted ValveN, and boiler-ValVeK, connected to a common stem, L, when arranged so asto operate together substantially as herein described, and for thepurpose specified.

VIRGIL D. GREEN.

Witnesses CHARLEs M. DUoAssr, LEONARD PAoHoLING.

